Intensity Modulated Radiation Therapy

Intensity modulated radiation therapy is a sophisticated radiation therapy delivery method that allows sparing of normal tissues and increased doses to be delivered to the primary target. Intensity modulated radiation therapy is preceded by CT scan-based treatment planning. The radiation oncologist, in conjunction with the treatment team, build a three-dimensional model of the patient inside the treatment planning computer. Normal tissues are delineated with a mouse and the area requiring treatment is outlined on each CT scan slice.

At this juncture, treatment delivery angles are selected by the care team. In general these number between five and seven. Each unique angle will deliver a beam of radiation treatment to the patient. From each position, critical normal structures will be blocked from having substantial radiation delivered to them Where a clear path exists between the treatment machine and the target, radiation will be delivered. Portions of the target blocked from the treatment team by critical normal structures will have radiation treatment delivered to them from a different angle. This process of blocking treatment delivery to one portion of the volume and allowing it to occur to a different portion of the volume is called intensity modulation. Treatments delivered in this fashion are termed intensity modulated radiation therapy treatments.

The latest version of intensity modulated radiation therapy treatment delivery software allows for continuous delivery of radiation as the machine rotates 360° in space. Powerful computers modulate the intensity of the radiation beams, the dose rate (a measure of how much radiation is coming out of the machine each minute,) and the rotational speed of the treatment machine through space. This form of treatment delivery is known as volumetric arc radiation therapy. On Varian linear accelerators, this technology is called RapidArc, and we are proud to have this technology at Piedmont Hospital. RapidArc treatments can accomplish a full IMRT treatment in less than 2 minutes, meaning a substantial reduction in the amount of time spent lying in the treatment position. RapidArc treatments are not appropriate in every treatment situation, and you are encouraged to discuss your suitability for this procedure with your radiation oncologist.

Piedmont Hospital was one of the first radiation therapy centers in Georgia to add intensity modulated radiation therapy treatments to its portfolio of offered treatments, and is very proud of our extensive experience with this technology.

Our physicians are highly experienced in treating all malignant and benign conditions for which radiation therapy is indicated. If you should have a question about whether or not a particular treatment is offered in our office, please feel free to contact our office by telephone.